Multicast Address Allocation (MALLOC) Working Group - Background
Background
Multicast address allocation is an essential part of using IP
multicast. Multicast addresses are an even more limited resource than
unicast addresses, and must be allocated dynamically if they are to
satisfy expected demand. To this end, the MALLOC WG is initially
proposing to define three protocols which work together to form a
global dynamic multicast address allocation mechanism.
These protocols will be:
- a "host to Address Allocation Server" protocol used by a host
to obtain one or more multicast addresses from an address allocation
server within its domain.
- an intra-domain server to server protocol that address allocation
serververs within the same domain can use to ensure that they do
not give out conflicting addresses.
- an inter-domain protocol to provide aggregatable multicast
address ranges to domains, which the servers in that domain can
then allocation individual multicast addresses out of. This
protocol will work in conjunction with the IDMR WG's Border
Gateway Multicast Protocol to provide a scalable inter-domain
multicast routing solution.
An important part of these protocols is that they do not necessarily
guarantee that a unique multicast address is allocated. They must,
however, at least provide a good statistical likelihood that the
address is unique within the scope it is allocated for.
Although mechanisms for enforcing policies for multicast address
allocation may be considered, setting any such policies is not
within the scope of this WG. Alternative multicast models are also
out of scope.
This figure attempts to characterise how these parts might fit
together:
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Last updated: June 14, 1999 by Dave Thaler